Electronic switches, such as MOSFETs or IGBTs, are widely used for switching electrical loads, such as motors, actors, or lamps in industrial applications. Drive circuits of electronic switches may include an over-current protection circuit and/or an over-temperature protection circuit. An over-current protection circuit is configured to drive the electronic switch such that a current through the switch is limited to a given value. An over-temperature protection circuit switches the switch off when the temperature reaches a given temperature, where the electronic switch may be switched on again when the temperature has fallen below the given temperature.
In particular in industrial applications it is desirable to have an all-purpose electronic switch that can switch different types of loads, such as motors or lamps, in particular incandescent lamps. Incandescent lamps include a filament that has a varying electrical resistance. When the lamp is cold, which means when the filament is cold, the electrical resistance of the filament is significantly lower than when the filament is hot. Thus, within a certain time period after switching on the cold lamp the current through the lamp is significantly higher than later when the filament is hot. When the lamp is switched on using an electronic switch that is over-current and over-temperature protected, the high current shortly after the time of switching on the lamp may cause the drive circuit to limit the current through the electronic switch. This, however, may cause a temperature of the electronic switch to increase to the critical value, so that the electronic switch may be switched off. This could be prevented by increasing the current limiting value. However, limiting the current through the electronic switch to a higher value may increase the risk of the electronic switch to be damaged when connected to a load having a damage, such as a short circuit.
There is, therefore, a need to provide a method for driving an electronic switch that allows an electronic switch to be used for different types of loads, and to provide an electronic circuit with an electronic switch.